Practically every passenger-carrying vehicle (such as sedans, convertibles, sports utility vehicles, station wagons, minivans, pick-up trucks and the like) comes equipped with an interior rearview mirror. Looking at the interior rearview mirror by the driver in order to see rearward is part and parcel of the driving task. Recently, a variety of features and accessories have been located at the interior rearview mirror, such as are described in “ADDED FEATURE AUTOMOTIVE MIRRORS” by Niall R. Lynam, Society of Automotive Engineers Technical Paper #980922, February 1998, the entire disclosure of which is hereby incorporated by reference herein. One such feature known in the art is placement of a video screen within the reflector area of an otherwise standard interior rearview mirror assembly. Thus, and as illustrated in FIG. 1, known interior rearview mirror assembly 10 comprises a mirror reflector element 14 housed in mirror case 12. Mirror case 12 and reflector element 14 are dimensioned symmetrical about the vertical centerline XX of assembly 10. Mirror housing 12 pivotally connects to mirror support arm 18. The pivot point of mirror support arm 18 is at vertical centerline XX. Vertical centerline XX essentially bisects mirror housing 12. Thus, distance ZZ to XX, as in FIG. 1, is the same dimension as distance XX to YY. Fixed reflectance mirror reflector element 14 includes a mirror reflector layer that reflects light incident thereon from behind the vehicle to which assembly 10 is mounted. However, a significant portion of the mirror reflector is removed to allow video screen 16 be viewed through the reflector element 14. Video screen 14 comprises a multi-pixel liquid crystal display that is disposed in case 12 behind reflector element 14. Images displayed by video screen 16 are thus viewed through reflector element 14.
Although the known assembly as described in FIG. 1 can operate in certain circumstances, there are disadvantages that limit its commercial use and success. In order to provide a display screen large enough to be viewed by a driver of the vehicle equipped with assembly 10, a relatively large video screen must be used (typically of diagonal dimension 1.5 inches or greater) which necessitates that a significant area of reflector layer be removed from reflector element 14 in order to allow display 16 be viewed therethrough. Thus, the rearward field of view from reflector element 14 is significantly degraded, leading to deterioration in the driver's ability to efficiently and safely use interior rearview mirror assembly 10 to see rearward. Also, the known assembly 10 utilizes a fixed reflectance element as mirror reflector element 14 that provides no ability for the driver to achieve glare relief when glaring conditions exist during night-driving. Because of such disadvantage, the known assembly 10 has not enjoyed widespread commercial success, particularly with automobile original equipment manufacturers, and there is a need for a rearview mirror assembly, including a video screen, that overcomes these disadvantages.